In recent years, there has increasingly been a rapid enhancement in terms of MMI (Man-Machine Interface) owing to an advancement in GUI (Graphical User Interface) in computers. Corresponding to such a trend, there increases an occasion in which the image data containing the images and characters are displayed in a variety of sizes, or printed by a printer, etc. and outputted.
On the other hand, with a diversification of the display information, a prevailing type of display device is, though low of its resolution in a so-called monochrome display, capable of displaying with multi-gradations. For example, the great majority of liquid crystal display devices exhibiting a low resolution are capable of 8- or 16-gradation display containing half-tones in addition to two gradations in black and white.
By the way, a comparatively inexpensive output device, especially a small-sized display device is generally low of the resolution and tends to be hard to see enough to worsen a visual recognizability because of an image the outline of which becomes conspicuous of sharp ruggedness when displaying binary image data consisting of rather definite binary data. A more remarkable tendency of this sort can be seen in the liquid crystal display often used for particularly a carriable type appliance such as a so-called notebook type personal computer because of rectangular dots being uniform in terms of display dots.
When outputting letter, i.e., characters having the same logic size (e.g., 10.5 point) to a display device and a printer that are defined as outputting devices, a letter image, viz., a character image actually displayed on the display device and a character image printed by the printer are expressed with different numbers of dots on account of a difference in resolution between the outputting devices. Therefore, the display device generally exhibiting a lower resolution than the printer comes to display a conspicuously rugged rough image of the character.
It is an object of the present invention, which was contrived under such circumstances, to provide an image half-tone processor capable of giving an easy-to-see display with a high visual recognizability by converting a primary binary image (an original binary image) into a multi-gradated image and outputting the image based on the multi-gradation expression in a system for outputting the binary image by use of an outputting device possible of expressing it with the multi-gradations containing half-tones.